Process for reclaiming distillation residues



Dec. 4, 1928.

R. E. POWELL lPROCESS FOR RECLAIMING DISTILLTION RESIDUES Filed Feb. 25, 192i RAYMOND E. POM/LL Snom/1to1 Patented Dec. 4, 1928.

lUNITED STATES naYMoND 4E. :PowELn or HOUSTON, mms, AssreNoIt To STANDARD ou. ,DEVELOP- MENT COMPANY, A. CORPORATION OF DELAWAR PROCESS FOR RECLAIMING DISTlILATION RESID'UEVS.

Application :filed February 2 5, 1925. Serial No. 11,425.

This invention relates to the art of reclaiming distillation residues and more particularly such residues as are left in redistilling lubricating stocks, which contain naphthenic compounds. Reference is made to the process and apparatus described in the application of Coleman 'and Hughes, Serial No. 691,162, filed February 7, 1924. The present invention is a development therefrom, and comprises as an essential feature the reduction of viscosity, fluxing, or dilution of the distillation residue before removing the naphthenic compounds. The material added to the residue may be gas oil, Diesel oil, tar from the operation of cracking apparatus, or the like. All suitable materials of this character are included in the term fluxing agent, as usedherein.

.As described in application Serial N o.

691,162, when lubricating stocks containing naphthenic acids are redistilled in the presence of caustic soda, or other sodium compound, a heavy residue comprising an intimate mixture of sodium naphthenate or other naphthenates and highv viscosity oil is left in the still. This residue will be referred to as caustic bottoms and the reclamation of oil from it will be described as illustrative of the invention. It is to be understood, however, that the process is not limited to treatment of this particular t-ype of residue.l

In carrying outlthe present invention, I add a viscosity-reducing material or the like to the caustic bottoms and then flow the resulting mixture upon a streanrof water.

' Undesirable constituents, especially naphthenic soaps, are dissolved in the water.

Stratification and separation are then efgas oil may be pre-heated, if necessary, and discharged into the line carrying the hot bottoms to the washing system or separator. The gas oil should ordinarily be at 500 F.

`-orthereabout to .temperature o the iluxed prevent too much cooli of the bottoms. ng

Depending u on particular conditions, the

bottoms may vary between about 300 F. to 650 F. vOrdinarlly better separation is secured at 1the higher temperatures within this range. The amountl to a still receiving the bottoms, or into the I pipe conveying the bottoms to the still. The temperature of the still may be maintained at about 550 to 600 F., and steam suiicient to secure` mixing and prevent coking may be injected. The fluxed bottoms are pumped from the still anddischarged into the separator, preferably without much loss of temperature. The bottoms may be mixed with the flux and the mixture then passed to the still or other suitable apparatus.

, When cracking coil tar or the like is the iuxing agent, it is generally desirable to use. about 50% of it by volume to obtain the desired viscosity. l

A preferred method of oper-ation will be described in connection with the accompanying drawing, in which the single ligure is an isometric view of one form of apparatus contemplated.

Referring to the drawings, numeral 1 denotes suitable apparatus, such as a still, into which bottoms and fluxing oil are introduced respectively through pipes 2 and'. Steam may be injected through line 4 and `any vapors involved may be taken off through line 5. The necessary amount of heat is supplied to the still, so that the Huxed oil may be taken oit through pipe 6 at a suitable temperature,'as described.

The Huxed oil then passes without much loss 'of heat into the trough 7 of settling tank 8. Water enters through pipe 9, which "head or slotted-head discharge, so as to spread the fluxed oil over the water.

The trough 7 discharges into the settling tank 8, a dam 9 being provided to maintain a fixed water level in the trough, and an apron 10 to prevent currents at the point of discharge into the tank. The settling tank may vary considerably in its form and dimentions. An advantageous layout is illustrated in the drawing. rlhe baffles 11, 12 and 13 are arranged in the tank in laterally staggered order so as to compel the contained liquids to travel very slowly and free from turbulence to the respective points of discharge. Valve-controlled draw-off pipes 14 and 15 are arranged at the bottom of the tank, and from a point near its top a drawoif pipe 16 leads to discharge into a second tank 17. Along'the bottom of t-he second tank a suitable heating means is arranged, illustrated in the drawing, Afor instance,las a steam coil 18. A valve-controlled drawoff.l pipe 19 is provided at the bottom of this tank and an adjustable swing draw-off pipe 20 at the top.

In tank- 8 stratification takes place with the formation of an upper layer of oil and a lower layer of water containing naphthen ates .dissolved from the oil.

At the start sufcient water is supplied to the tank to bring the level up well to the top and after the feed of residuum is established and stratification has taken place, the lower layer is -drawn off' at such a rate` as to allow an adequate accumulation of the upper layers,` permitting suitable draw-off thereof into the second tank 17. By proper regulation of the draw-ofi' valves the process mayV thus be made to function in continuous manner, the stratiicatlon levels being maintained at relatively constant points. The

V:its

oil layer and some naphthenic compounds pass over to the second tank, and here final stratification and separation allows of the withdrawing of the clean oil from the top by means of the swing pipe 20. From the bottom of the tank the naphthenic compounds, occurring here chieiy as naphthenates of the heavyv metals, especially iron, are withdrawn for further treatment. This treatment may vary somewhat, but preferably comprises subjecting the naphthenate mixture, it being in the form of emulsion, to the action o f sulfuric acid. This serves todecompose the naphthenates and set free the naphthenic acid and the emulsified oil, and on settling these constituents can be drawn off from the ltop and the sludge run to waste.

rating and treating them independently,

but the separation may proceed along the main lines of division of the oil on the one hand and the water-soluble naphthenates on the other.v rlhewater-soluble naphthenates may be suitably recovered from the water, as by salting out or by concentration, and these compounds are then available for various uses as desired.

If preferred, the stratification levels can be so maintained that the emulsifed heavy metal naphthenate layer may be drawn olf fromy tank 8 and further separated, as mentioned in the foregoing, instead of being carried over into tank 17 and there separated; that is, the precise point at which the separation of the heavy metal emulsilied Various changes may be made in the dei scribed embodiments of the invention, within the scope of the appended claims, in which it is my intention to claim" all novelty inherent in the invention as broadly as the prior art permits.

I claim:

1. Process of reclaiming a naphthenic distillation residue, which comprises adding a llux'in'g material comprising a hydrocarbon oil of viscosity less than that of said residue and of boiling range high enough to ensure presence in liquid state thereto, discharging the fluxed residue while hot upon the surface of gently moving water, then retarding the iowV and allowing stratification to take place, and separately withdrawing the oil and the water containing dissolved naphthenic compounds.

2. Process of reclaiming a naphthenic distillation residue, which comprises mixing' the residue with gas oil, discharging the fluxed residuefwhile hot upon the surface of flowing water, then allowing stratification to occur, withdrawing the water containing dissolved naphthenates from the bottom layer, further settling the upper layers, withdrawing the oil from the top, and then withdrawing heavy metal naphthenates.

' 3. Process of reclaiming a distillation residue containing water-soluble constitu-r ents, which comprises mixing a fluxing agent with a hot body of the residue, maintaining the heat of the mixture, discharging the hot fluxed residue upon the surface of a stream of water, allowing stratification to take place, and. separately withdrawing the\ol 130.

and the Water containing dissolved constiting suiicient steam*4 to mix the bottoms and uents. y gas oil, discharging the luxed residue upon 1G 4. Process of removing naphthenates from the surface of a stream of Water, allowlng caustic soda bottoms, which comprises chargstratification to take place, and separately 5 ing the bottoms while hot in a still, adding withdrawing the -oil and the Water containrelatively cool gas oil in amount sufficient to ing dissolved sodium naphthenates. iiux the bottoms, heating the still to maintain the temperature of its contents, inject- RAYMOND E. POWELL. 

